A variety of sanitizer compositions containing anionic surfactants and acid as the essential ingredients providing anti-microbial activity are known. While the known compositions meet or exceed accepted standards for anti-microbial activity, a common and troublesome deficiency of many of the known compositions is that they create undesirably high foam levels, especially when used in cleaning-in-place or spray applications. The problem is magnified by the use of treated or deionized water as a diluent before use because treated or deionized water results in higher foaming than hard water. Since sanitizer compositions are typically supplied as concentrates for subsequent dilution by the user, it is desirable that the use composition have low foaming characteristics whatever the nature of the diluent water chosen by the user.
It is recognized that the foaming problem is caused by the anionic surfactant but the problem is not easily resolved because anionic surfactants such as linear alkyl aryl sulfonic acids are desirable for their recognized anti-microbial function activity and because such known anionic surfactants are considered attractive for their good anti-microbial activity and low cost. One common solution to the foaming problem is to add silicone foam reducing agents but silicones are undesirable in food and milk plant sanitizer compositions because the silicones tend to build up on equipment and harbor bacteria.
One solution to the foaming problem is to substitute the commonly used high foaming surfactants such as linear alkyl aryl sulfonic acids with anionic surfactants which are low foaming in the acid sanitizer environment as disclosed in U.S. Pat. No. 3,650,934. In this invention, the alternative of incorporating a foam suppressant into the composition whereby the advantages of common and widely available anionic surfactants are obtained with the elimination or reduction of the high foaming problem.